In the United States, water heaters traditionally have a tank configured to hold a quantity of heated water. Tanked water heaters are advantageous in that they can provide a relatively large volume of hot water from a relatively tow level energy source, but they are inefficient in that they maintain a supply of hot water even when such water is not being used. Such water heaters are also problematic in that they can therefore “run out of hot water” from time to time. Still further such traditional tank heaters can pose a danger of explosion if the relief valve fails due to limestone, calcium or other deposits.
One solution is to use a tankless water heater that heats water on demand. Tankless water heaters are known that use resistance heating, and heating via infrared radiation. An exemplary embodiment of an infrared (IR) water heater is described in U.S. Pat. No. 4,510,890 to Cowan, which uses IR radiation to cause combustion of an air/gas mixture that can be used to heat water in a tank. Such a configuration is disadvantageous because the IR radiation is used to combust the mixture, rather than heat the water directly. That leads to inefficiencies, and moreover the combustion of the mixture is a potential danger.
Cowan and all other extrinsic materials discussed herein are incorporated by reference in their entirety. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
Another known infrared water heater device is described in EPO patent no. 279767 to Ripka, et al. However, the Ripka heater is disadvantageous as it utilizes a portion of the heat produced as a space heater rather than concentrate the infrared radiation on the piping. U.S. Pat. No. 5,685,997 to LoPresti discusses a plasma oscillator water heater that uses a hollow chamber to heat water outside of the chamber, but such heater is impractical for residential needs, and fails to utilize an infrared light source. Still further devices are described in U.S. pat. pub. no. 2011/0058797 to Servidio (publ. Mar. 2011) and U.S. pat. publ. no. 2012/0080422 to Chung et al. (Publ. Apr. 2012), each of which suffers from one or more disadvantages.
It is also known for a water heater to use the sun as its source of heating energy. For example, U.S. patent appl. no. 2010/0192944 to Gruber discusses a solar water heater and distiller device having multiple lenses arranged on the external wall through which IR radiation can pass. In another design, U.S. Pat. No. 4,334,522 to Dukess discusses a spherical solar energy device through which IR radiation from the sun can pass and be directed onto an inner member's surface. These solar water heaters each suffer from one or more disadvantages including, for example, a dependency upon solar energy and an inefficient use of IR radiation.
Thus, there is still a need for improved water heaters having multiple fluid conduits that are disposed about one or more heating devices.